A lithium extraction adsorbent, a preparation method and application thereof

Abstract

The present application provides a kind of lithium extraction adsorbent and its preparation method and application, the lithium extraction adsorbent includes resin-based material of grafted crown ether group, and the active site of α-ZrP adsorption loaded on the surface of resin-based material.The present application makes it load abundant active site of α-ZrP adsorption under the premise of loading crown ether group showing high selectivity to lithium ion on resin-based material, crown ether group and active site of α-ZrP adsorption can play the role of synergistic adsorption lithium ion, while ensuring the capacity of lithium extraction adsorbent, improve the affinity to lithium ion, so that lithium extraction adsorbent can avoid the interference of magnesium, calcium and other metal ions.Therefore, the lithium extraction adsorbent shows high selective adsorption and high adsorption capacity to lithium ion in solution, and the lithium extraction adsorbent production cost and solution loss rate is lower, can realize repetitive use.

Description

Technical Field

[0001] This invention belongs to the field of adsorption materials technology, specifically relating to a lithium extraction adsorbent, its preparation method, and its application. Background Technology

[0002] In recent years, due to the widespread use of lithium-ion batteries in electronic products and electric vehicles, global lithium consumption has grown rapidly. Approximately 76% of the world's lithium resources exist in brine. Currently, lithium extraction methods include evaporation crystallization, membrane filtration, precipitation, extraction, and adsorption. Among these, the adsorption method utilizes adsorbents to selectively adsorb lithium ions. After adsorption, the adsorbent can be desorbed by acid washing, thus separating lithium ions from other ions. This method has advantages such as easy regeneration, simple operation, and high recovery rate, making it one of the most promising lithium extraction methods.

[0003] Currently, based on the properties of lithium extraction adsorbents, they can be divided into organic adsorbents and inorganic adsorbents. Organic adsorbents are mainly ion exchange resins, which have limited adsorption capacity for lithium ions. Inorganic adsorbents are more widely used. Inorganic adsorbents mainly include manganese-based, titanium-based, aluminum-based, and iron-based oxides. These adsorbents have relatively complex preparation methods, poor reusability, and are easily dissolved.

[0004] α-Zr(HPO4)2·H2O (denoted as α-ZrP) is a solid acid layered material with high thermal stability, chemical stability and strong acid and alkali resistance. The H+ of the phosphate group in this type of material can diffuse freely in the space within the layer, and it has excellent ion exchange performance. It can be used as an adsorbent for lithium ions with a large adsorption capacity and long service life, but its adsorption selectivity for lithium ions is limited.

[0005] Therefore, from the perspective of existing technology, the main problems of currently synthesized lithium extraction adsorbents are high production costs, high solubility, low adsorption capacity, and poor selectivity.

[0006] In summary, there is an urgent need to design a lithium extraction adsorbent that is low in cost, has a low solubility, high adsorption capacity, and excellent lithium-ion adsorption selectivity. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to provide a lithium extraction adsorbent, its preparation method, and its applications. This invention loads a resin-based material with crown ether groups exhibiting high selectivity for lithium ions, while simultaneously loading it with abundant α-ZrP adsorption active sites. The crown ether groups and α-ZrP adsorption active sites synergistically adsorb lithium ions, enhancing the affinity for lithium ions while maintaining the adsorbent's capacity. This allows the adsorbent to avoid interference from metal ions such as magnesium and calcium. Therefore, this lithium extraction adsorbent exhibits high selectivity and high adsorption capacity for lithium ions in solution, and it also boasts low production costs and low solubility, enabling reusability.

[0008] To achieve this objective, the present invention adopts the following technical solution:

[0009] In a first aspect, the present invention provides a lithium extraction adsorbent comprising a resin-based material grafted with crown ether groups and α-ZrP adsorption active sites loaded on the surface of the resin-based material.

[0010] This invention, by loading crown ether groups exhibiting high selectivity for lithium ions onto a resin-based material, further enriches it with α-ZrP adsorption active sites. The crown ether groups and α-ZrP adsorption active sites synergistically adsorb lithium ions, enhancing the affinity for lithium ions while maintaining the capacity of the lithium-extracting adsorbent. This allows the lithium-extracting adsorbent to avoid interference from metal ions such as magnesium and calcium. Therefore, this lithium-extracting adsorbent exhibits high selectivity and high adsorption capacity for lithium ions in solution, and its production cost and solubility are low, enabling reusability. As a preferred embodiment of this invention, the crown ether group content in the resin-based material is 0.5-2 mmol / L, for example, 0.5 mmol / L, 1 mmol / L, 1.5 mmol / L, or 2 mmol / L.

[0011] In this invention, the crown ether group possesses a nanoscale porous structure. The negatively charged oxygen atoms on its ether ring adsorb lithium ions through dipole-charge electrostatic interactions, and its unique structure gives it specificity for lithium ions. Therefore, a crown ether group content of 0.5-2 mmol / L further enhances the selectivity of the adsorbent for lithium ions.

[0012] Preferably, the resin-based material includes a cation exchange resin.

[0013] In this invention, the cation exchange resin is a polymer obtained by polymerizing styrene and divinylbenzene and then sulfonating it with sulfuric acid. The cation exchange resin has high mechanical strength, stable chemical properties, and a long service life under normal conditions.

[0014] Preferably, the cation exchange resin comprises chloromethylated polystyrene resin and / or chloromethyl methacrylate.

[0015] As a preferred embodiment of the present invention, the loading of the α-ZrP adsorption active sites is 30wt%-60wt% of the mass of the resin-based material, for example, it can be 30wt%, 40wt%, 50wt% or 60wt%.

[0016] In this invention, if the loading of α-ZrP adsorption active sites is too small, the adsorption capacity of the lithium extraction adsorbent will be reduced; if the loading of α-ZrP adsorption active sites is too large, the selectivity of the lithium extraction adsorbent for lithium ions will be affected. Secondly, this invention provides a method for preparing the lithium extraction adsorbent as described in the first aspect, the method comprising the following steps:

[0017] The lithium extraction adsorbent is obtained by mixing a resin-based material grafted with crown ether groups, a solution containing a zirconium source, and a solution containing a phosphorus source, and then reacting the mixture.

[0018] The preparation process provided by this invention is simple and can overcome the problems of low lithium extraction selectivity and capacity of existing resin-based lithium extraction adsorbents.

[0019] As a preferred technical solution of the present invention, the solid-liquid ratio of the resin-based material grafted with crown ether groups and the zirconium-containing solution is 1g:(3-5)mL, for example, it can be 1g:3mL, 1g:3.5mL, 1g:4mL, 1g:4.5mL or 1g:5mL, etc.

[0020] In this invention, if the solid-liquid ratio of the resin-based material grafted with crown ether groups to the zirconium-containing solution is too small, the selectivity of the lithium-extracting adsorbent for lithium ions will decrease; if the solid-liquid ratio of the resin-based material grafted with crown ether groups to the zirconium-containing solution is too large, the lithium adsorbent's capacity to adsorb lithium will decrease.

[0021] Preferably, the method for preparing the zirconium-containing source solution includes:

[0022] The zirconium source is dissolved in a solvent to obtain the zirconium-containing solution.

[0023] Preferably, the solid-liquid ratio of the zirconium source and the solvent is 1g:(4-6)mL, for example, it can be 1g:4mL, 1g:4.5mL, 1g:mL, 1g:5.5mL or g:mL, etc.

[0024] Preferably, the solvent includes ethanol and / or water, and more preferably ethanol and water.

[0025] Preferably, the volume ratio of ethanol to water is (6-8):1, for example, it can be 6:1, 6.5:1, 7:1, 7.5:1 or 8:1, etc.

[0026] Preferably, the concentration of the phosphorus source solution is 1.5-3 mol / L, for example, it can be 1.5 mol / L, 2 mol / L, 2.5 mol / L or 3 mol / L, etc.

[0027] In this invention, if the concentration of the phosphorus source solution is too low, the reaction rate will be reduced; if the concentration of the phosphorus source solution is too high, the reaction rate will be too fast, and the formed α-ZrP will be uneven.

[0028] Preferably, the molar ratio of the zirconium source in the zirconium-containing solution to the phosphorus source in the phosphorus-containing solution is 1:(1-3), for example, it can be 1:1, 1:1.5, 1:2, 1:2.5 or 1:3, etc.

[0029] In this invention, if the molar ratio of zirconium source in the zirconium source solution to phosphorus source in the phosphorus source solution is too small, the crystallinity of α-ZrP will decrease and the structure will be unstable; if the molar ratio of zirconium source in the zirconium source solution to phosphorus source in the phosphorus source solution is too large, the particle size of α-ZrP will be larger and the specific surface area will be reduced, thereby reducing the effective adsorption active sites for lithium.

[0030] Preferably, the zirconium source includes ZrOCl2·8H2O.

[0031] Preferably, the phosphorus source includes phosphoric acid.

[0032] As a preferred technical solution of the present invention, the mixing method includes:

[0033] The resin-based material grafted with crown ether groups is blended with a zirconium-containing solution, and then a phosphorus-containing solution is added and mixed.

[0034] In this invention, the above-mentioned mixing method helps to obtain α-ZrP with high thermal stability, chemical stability and strong acid and alkali resistance.

[0035] Preferably, the blending process is accompanied by stirring.

[0036] In this invention, stirring allows for more thorough mixing of the resin-based material grafted with crown ether groups and the zirconium-containing solution.

[0037] Preferably, the blending temperature is 70-80℃, for example, 70℃, 72℃, 74℃, 76℃, 78℃ or 80℃, and the blending time is 1-2h, for example, 1h, 1.2h, 1.4h, 1.6h, 1.8h or 2h.

[0038] In this invention, blending at 70-80℃ for 1-2 hours allows the solvent to fully evaporate.

[0039] Preferably, the reaction temperature is 90-120℃, for example, 90℃, 100℃, 110℃ or 120℃, and the time is 24-48h, for example, 24h, 30h, 36h, 42h or 48h.

[0040] In this invention, if the reaction temperature is too low, the α-ZrP crystals will be incomplete and the structure will be unstable; if the reaction temperature is too high, the reaction rate will be too fast, and the formed α-ZrP will easily agglomerate, reducing the effective adsorption sites of lithium.

[0041] As a preferred embodiment of the present invention, the preparation steps of the resin-based material grafted with crown ether groups include:

[0042] (a) Benzo-12-crown-4, organic acid, nitric acid and organic solvent are mixed and reacted to obtain nitrobenzo-12-crown-4;

[0043] (b) The nitrobenz-12-crown-4, the reducing agent, and the organic solvent are mixed and reacted to obtain aminobenzo-12-crown-4;

[0044] (c) The resin-based material, the aminobenzo-12-crown-4 and the organic solvent are mixed and reacted to obtain the resin-based material with the grafted crown ether group.

[0045] In this invention, the reaction equation in step (a) is as follows:

[0046]

[0047] In this invention, the reaction equation in step (b) is as follows:

[0048]

[0049] In this invention, when the resin-based material is a cation exchange resin, the reaction equation in step (c) is as follows:

[0050]

[0051] The present invention prepares a resin-based material grafted with crown ether groups through the above steps, which significantly improves the selective adsorption of lithium ions by the adsorbent.

[0052] As a preferred embodiment of the present invention, the organic acid in step (a) includes glacial acetic acid.

[0053] Preferably, the organic solvent in step (a) includes chloroform.

[0054] Preferably, the mass concentration of nitric acid in step (a) is 80-90%, for example, it can be 80%, 82%, 84%, 86%, 88% or 90%, etc.

[0055] Preferably, the solid-liquid ratio of benzo-12-crown-4 and the organic solvent in step (a) is 1g:(13-17)mL, for example, it can be 1g:13mL, 1g:14mL, 1g:15mL, 1g:16mL or 1g:17mL, etc.

[0056] Preferably, the solid-liquid ratio of benzo-12-crown-4 and organic acid in step (a) is 1g:(13-17)mL, for example, it can be 1g:13mL, 1g:14mL, 1g:15mL, 1g:16mL or 1g:17mL.

[0057] In this invention, the solid-liquid ratio of benzo-12-crown-4 and organic acid is 1g:(13-17)mL, which can reduce the viscosity of the reaction system.

[0058] Preferably, the molar ratio of benzo-12-crown-4 and nitric acid in step (a) is 1:(0.6-1), for example, it can be 1:0.6, 1:0.7, 1:0.8, 1:0.9 or 1:1, etc.

[0059] In this invention, if the molar ratio of benzo-12-crown-4 to nitric acid is too small, the reaction will be incomplete and the amount of nitrobenzo-12-crown-4 generated will be too small; if the molar ratio of benzo-12-crown-4 to nitric acid is too large, the reaction will be too vigorous and side reactions will easily occur.

[0060] Preferably, the reaction temperature in step (a) is 20-30°C, for example, 20°C, 22°C, 24°C, 26°C, 28°C or 30°C, and the reaction time is 12-24h, for example, 12h, 18h or 24h.

[0061] In this invention, the reaction to obtain nitrobenzene-12-crown-4 is carried out at 20-30°C, which can effectively control the reaction rate and result in a product with high purity.

[0062] Preferably, the reducing agent in step (b) includes hydrazine hydrate and / or sodium borohydride.

[0063] In this invention, hydrazine hydrate is an inorganic compound with the chemical formula N₂H₄·H₂O. Hydrazine hydrate exists as a liquid dimer and is miscible with water and ethanol; it has extremely strong reducing properties and can be used as a reducing agent.

[0064] Preferably, the organic solvent in step (b) includes anhydrous ethanol.

[0065] Preferably, the solid-liquid ratio of nitrobenz-12-crown-4 and the organic solvent in step (b) is 1g:(15-20)mL, for example, it can be 1g:15mL, 1g:16mL, 1g:17mL, 1g:18mL, 1g:19mL or 1g:20mL, etc.

[0066] Preferably, the mass ratio of nitrobenzo-12-crown-4 to the reducing agent in step (b) is 1:(0.1-0.3), for example, it can be 1:0.1, 1:0.15, 1:0.2, 1:0.25 or 1:0.3, etc.

[0067] In this invention, if the mass ratio of nitrobenz-12-crown-4 to the reducing agent is 1:(0.1-0.3), it helps the reduction reaction to occur completely, with fewer side reactions and higher purity of the resulting product.

[0068] Preferably, the reaction temperature in step (b) is 75-85°C, for example, 75°C, 80°C or 85°C, and the reaction time is 8-16h, for example, 8h, 10h, 12h, 14h or 16h.

[0069] In this invention, the reaction between nitrobenz-12-crown-4 and the reducing agent is carried out at 75-85°C, which allows the reduction reaction to occur completely with fewer side reactions and a higher purity of the resulting product.

[0070] Preferably, the organic solvent in step (c) includes N,N-dimethylamide.

[0071] Preferably, a pH adjuster is added during the mixing process in step (c) so that the pH value of the resulting mixed solution is 9-13, for example, 9, 10, 11, 12 or 13.

[0072] In this invention, a pH value of 9-13 is beneficial for controlling the reaction rate and improving the grafting rate of aminobenzo-12-crown-4 onto the cation exchange resin.

[0073] Preferably, the pH adjuster comprises an alkaline substance.

[0074] Preferably, the alkaline substance includes any one or a combination of at least two of sodium carbonate, sodium bicarbonate, or sodium hydroxide.

[0075] Preferably, the reaction temperature in step (c) is 25-60°C, for example, 25°C, 30°C, 40°C, 50°C or 60°C, and the reaction time is 2-5 hours, for example, 2 hours, 3 hours, 4 hours or 5 hours.

[0076] In this invention, the reaction between the resin-based material and aminobenzo-12-crown-4 is carried out at 25-60°C for 2-5 hours, which helps to control the reaction rate and improve the grafting rate of aminobenzo-12-crown-4 on the cation exchange resin.

[0077] Preferably, the ratio of the resin-based material, the aminobenzo-12-crown-4, and the organic solvent in step (c) is 1g:(8-10)mL:(5-7)mL. For example, the ratio of the resin-based material to the aminobenzo-12-crown-4 can be 1g:8mL, 1g:8.5mL, 1g:9mL, 1g:9.5mL, or 1g:10mL, and the ratio of the resin-based material to the organic solvent can be 1g:5mL, 1g:5.5mL, 1g:6mL, 1g:6.5mL, or 1g:7mL, etc.

[0078] In this invention, if the ratio of resin-based material to aminobenzo-12-crown-4 is too small, the content of aminobenzo-12-crown-4 on the resin-based material will be too high, the diffusion rate of lithium ions will decrease, and the adsorption capacity of the lithium extraction adsorbent will be reduced. If the ratio of resin-based material to aminobenzo-12-crown-4 is too high, the number of crown ether groups with high selectivity for lithium ions on the lithium extraction adsorbent will be too low, and the selectivity of the lithium extraction adsorbent for lithium ions will be reduced.

[0079] As a preferred technical solution of the present invention, the preparation method includes the following steps:

[0080] (1) Dissolve benzo-12-crown-4 in chloroform and add glacial acetic acid, then add nitric acid with a mass concentration of 80-90% dropwise and mix. Then carry out the reaction at 20-30℃ for 12-24h. After the reaction is completed, wash and dry the product to obtain nitrobenzene-12-crown-4.

[0081] The solid-liquid ratio of benzo-12-crown-4 to chloroform is 1 g:(13-17) mL, the solid-liquid ratio of benzo-12-crown-4 to glacial acetic acid is 1 g:(13-17) mL, and the molar ratio of benzo-12-crown-4 to nitric acid is 1:(0.6-1).

[0082] (2) The nitrobenz-12-crown-4 was placed in anhydrous ethanol, and then hydrazine hydrate was added. The reaction was carried out at 75-85℃ for 8-16 h. After the reaction was completed, the product was washed and dried to obtain aminobenzo-12-crown-4.

[0083] The solid-liquid ratio of nitrobenz-12-crown-4 to anhydrous ethanol is 1 g:(15-20) mL, and the mass ratio of nitrobenz-12-crown-4 to hydrazine hydrate is 1:(0.1-0.3).

[0084] (3) Add the cation exchange resin to N,N dimethylamide and stir evenly, then add the aminobenzo-12-crown-4, and add alkaline substances to control the pH of the reaction system to 9-13. Stir the reaction at 25-60℃ for 2-5 hours. After the reaction is completed, wash the product to obtain the cation exchange resin grafted with crown ether groups.

[0085] The ratio of cation exchange resin, aminobenzo-12-crown-4 and N,N dimethylamide is 1 g:(8-10) mL:(5-7) mL.

[0086] (4) In a mixed solvent of ethanol and water with a volume ratio of (6-8):1, a zirconium source is added and stirred to dissolve, resulting in a zirconium source-containing solution. Then, the cation exchange resin grafted with crown ether groups is immersed in the zirconium source-containing solution and stirred at 70-80℃ for 1-2 hours. Subsequently, a phosphoric acid solution with a concentration of 1.5-3 mol / L is added, and the reaction is carried out at 90-120℃ for 24-48 hours. After the reaction is completed, the product is washed and dried to obtain a lithium extraction adsorbent.

[0087] The solid-liquid ratio of zirconium source and mixed solvent is 1g:(4-6)mL, the solid-liquid ratio of cation exchange resin grafted with crown ether group and zirconium source solution is 1g:(3-5)mL, and the molar ratio of zirconium source in zirconium source solution to phosphoric acid in phosphoric acid solution is 1:(1-3).

[0088] The preparation method provided by this invention can simultaneously load crown ether groups that exhibit high selectivity for lithium ions onto a resin matrix and precipitate α-ZrP in situ, thereby loading it with abundant α-ZrP adsorption active sites. This can play a synergistic role in adsorbing lithium ions, improving the affinity for lithium ions while ensuring the capacity of the lithium-extracting adsorbent.

[0089] Thirdly, the present invention provides an application of the lithium extraction adsorbent as described in the first aspect in lithium extraction from salt lakes.

[0090] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0091] Compared with the prior art, the present invention has the following beneficial effects:

[0092] This invention loads a resin-based material with crown ether groups exhibiting high selectivity for lithium ions, while simultaneously loading it with abundant α-ZrP adsorption active sites. The crown ether groups and α-ZrP adsorption active sites synergistically adsorb lithium ions, enhancing the affinity for lithium ions while maintaining the capacity of the lithium-extracting adsorbent. This allows the adsorbent to avoid interference from metal ions such as magnesium and calcium. Therefore, this lithium-extracting adsorbent exhibits high selectivity and high adsorption capacity for lithium ions in solution, and it also boasts low production cost and low solubility, enabling reusability. Attached Figure Description

[0093] Figure 1 The infrared spectrum analysis diagram is shown for the lithium extraction adsorbent prepared in Example 1 of this invention. Detailed Implementation

[0094] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0095] Example 1

[0096] This embodiment provides a lithium extraction adsorbent, which includes a resin-based material grafted with crown ether groups and α-ZrP adsorption active sites loaded on the surface of the resin-based material.

[0097] The resin-based material for grafting crown ether groups is a cation exchange resin for grafting crown ether groups, wherein the cation exchange resin is chloromethylated polystyrene resin, and the content of the crown ether groups is 1 mmol / L.

[0098] The loading of the α-ZrP adsorption active sites is 40 wt% of the resin-based material.

[0099] This embodiment also provides a method for preparing the above-mentioned lithium extraction adsorbent, the preparation method comprising the following steps:

[0100] (1) Benzo-12-crown-4 was dissolved in chloroform and glacial acetic acid was added. Then, nitric acid with a mass concentration of 85% was added dropwise and mixed. The reaction was carried out at 25°C for 18 hours. After the reaction was completed, the product was washed and dried to obtain nitrobenzo-12-crown-4.

[0101] The solid-liquid ratio of benzo-12-crown-4 to chloroform is 1 g: 15 mL, the solid-liquid ratio of benzo-12-crown-4 to glacial acetic acid is 1 g: 15 mL, and the molar ratio of benzo-12-crown-4 to nitric acid is 1: 0.8.

[0102] (2) The nitrobenz-12-crown-4 was placed in anhydrous ethanol, and then hydrazine hydrate was added. The reaction was carried out at 80°C for 12 h. After the reaction was completed, the product was washed and dried to obtain aminobenzo-12-crown-4.

[0103] The solid-liquid ratio of nitrobenz-12-crown-4 to anhydrous ethanol is 1 g: 17 mL, and the mass ratio of nitrobenz-12-crown-4 to hydrazine hydrate is 1: 0.2.

[0104] (3) Chloromethylated polystyrene resin was added to N,N dimethylamide and stirred evenly. Then, aminobenzo-12-crown-4 was added, and sodium carbonate was added to control the pH of the reaction system to 11. The reaction was stirred at 40°C for 3 hours. After the reaction was completed, the product was washed to obtain a cation exchange resin grafted with crown ether groups.

[0105] The ratio of chloromethylated polystyrene resin, aminobenzo-12-crown-4 and N,N dimethylamide is 1g:9mL:6mL.

[0106] (4) In a mixed solvent of ethanol and water with a volume ratio of 7:1, ZrOCl2·8H2O was added and stirred to dissolve, resulting in a solution containing ZrOCl2·8H2O. Then, the cation exchange resin grafted with crown ether groups was immersed in the solution containing ZrOCl2·8H2O and stirred at 75°C for 1.5 h. Subsequently, a phosphoric acid solution with a concentration of 2 mol / L was added, and the reaction was carried out at 100°C for 36 h. After the reaction was completed, the product was washed with deionized water and dried to obtain the lithium extraction adsorbent.

[0107] The solid-liquid ratio of ZrOCl2·8H2O to the mixed solvent is 1g:5mL, the solid-liquid ratio of the cation exchange resin grafted with crown ether groups to the solution containing ZrOCl2·8H2O is 1g:4mL, and the molar ratio of ZrOCl2·8H2O in the solution containing ZrOCl2·8H2O to phosphoric acid in the phosphoric acid solution is 1:2.

[0108] Figure 1 The infrared spectrum analysis of the lithium extraction adsorbent prepared in this embodiment is shown. It can be seen from the figure that at 3450 cm⁻¹... 1 1632cm- 1 1114cm- 1 980cm- 1 752cm- 1 547cm- 1 The characteristic absorption peak of α-ZrP is at 3344 cm⁻¹. 1 and 2923cm- 1 The position corresponds to the -NH2 group of the crown ether, at 1716 cm⁻¹1 The position corresponds to the C-C bond in the benzene ring, at 1513 cm⁻¹. 1 The position corresponds to an NH bond.

[0109] Example 2

[0110] This embodiment provides a lithium extraction adsorbent, which includes a resin-based material grafted with crown ether groups and α-ZrP adsorption active sites loaded on the surface of the resin-based material.

[0111] The resin-based material for grafting crown ether groups is a cation exchange resin for grafting crown ether groups, wherein the cation exchange resin is chloromethylated polystyrene resin, and the content of the crown ether groups is 2 mmol / L.

[0112] The loading of the α-ZrP adsorption active sites is 30 wt% of the resin-based material.

[0113] This embodiment also provides a method for preparing the above-mentioned lithium extraction adsorbent, the preparation method comprising the following steps:

[0114] (1) Dissolve benzo-12-crown-4 in chloroform and add glacial acetic acid, then add nitric acid with a mass concentration of 85% dropwise and mix. Then carry out the reaction at 25°C for 12 h. After the reaction is completed, wash and dry the product to obtain nitrobenzene-12-crown-4.

[0115] The solid-liquid ratio of benzo-12-crown-4 to chloroform is 1 g: 13 mL, the solid-liquid ratio of benzo-12-crown-4 to glacial acetic acid is 1 g: 13 mL, and the molar ratio of benzo-12-crown-4 to nitric acid is 1: 0.6.

[0116] (2) The nitrobenz-12-crown-4 was placed in anhydrous ethanol, and then hydrazine hydrate was added. The reaction was carried out at 75°C for 16 h. After the reaction was completed, the product was washed and dried to obtain aminobenzo-12-crown-4.

[0117] The solid-liquid ratio of nitrobenz-12-crown-4 to anhydrous ethanol is 1 g: 15 mL, and the mass ratio of nitrobenz-12-crown-4 to hydrazine hydrate is 1: 0.1.

[0118] (3) Chloromethylated polystyrene resin was added to N,N dimethylamide and stirred evenly. Then, aminobenzo-12-crown-4 was added, and sodium carbonate was added to control the pH of the reaction system to 9. The reaction was stirred at 60°C for 2 hours. After the reaction was completed, the product was washed to obtain a cation exchange resin grafted with crown ether groups.

[0119] The ratio of chloromethylated polystyrene resin, aminobenzo-12-crown-4 and N,N dimethylamide is 1g:10mL:5mL.

[0120] (4) In a mixed solvent of ethanol and water with a volume ratio of 6:1, ZrOCl2·8H2O was added and stirred to dissolve, resulting in a solution containing ZrOCl2·8H2O. Then, the cation exchange resin grafted with crown ether groups was immersed in the solution containing ZrOCl2·8H2O and stirred at 70°C for 2 hours. Subsequently, a phosphoric acid solution with a concentration of 1.5 mol / L was added, and the reaction was carried out at 120°C for 24 hours. After the reaction was completed, the product was washed with deionized water and dried to obtain the lithium extraction adsorbent.

[0121] The solid-liquid ratio of ZrOCl2·8H2O to the mixed solvent is 1g:4mL, the solid-liquid ratio of the cation exchange resin grafted with crown ether groups to the solution containing ZrOCl2·8H2O is 1g:5mL, and the molar ratio of ZrOCl2·8H2O in the solution containing ZrOCl2·8H2O to phosphoric acid in the phosphoric acid solution is 1:3.

[0122] Example 3

[0123] This embodiment provides a lithium extraction adsorbent, which includes a resin-based material grafted with crown ether groups and α-ZrP adsorption active sites loaded on the surface of the resin-based material.

[0124] The resin-based material for grafting crown ether groups is a cation exchange resin for grafting crown ether groups, wherein the cation exchange resin is chloromethylated polystyrene resin, and the content of the crown ether groups is 0.5 mmol / L;

[0125] The loading of the α-ZrP adsorption active sites is 60 wt% of the resin-based material.

[0126] This embodiment also provides a method for preparing the above-mentioned lithium extraction adsorbent, the preparation method comprising the following steps:

[0127] (1) Dissolve benzo-12-crown-4 in chloroform and add glacial acetic acid, then add nitric acid with a mass concentration of 85% dropwise and mix. Then carry out the reaction at 25°C for 24 hours. After the reaction is completed, wash and dry the product to obtain nitrobenzene-12-crown-4.

[0128] The solid-liquid ratio of benzo-12-crown-4 to chloroform is 1g:13mL, the solid-liquid ratio of benzo-12-crown-4 to glacial acetic acid is 1g:13mL, and the molar ratio of benzo-12-crown-4 to nitric acid is 1:1.

[0129] (2) The nitrobenz-12-crown-4 was placed in anhydrous ethanol, and then hydrazine hydrate was added. The reaction was carried out at 85°C for 8 hours. After the reaction was completed, the product was washed and dried to obtain aminobenzo-12-crown-4.

[0130] The solid-liquid ratio of nitrobenz-12-crown-4 to anhydrous ethanol is 1 g: 20 mL, and the mass ratio of nitrobenz-12-crown-4 to hydrazine hydrate is 1: 0.3.

[0131] (3) Chloromethylated polystyrene resin was added to N,N dimethylamide and stirred evenly. Then, aminobenzo-12-crown-4 was added, and sodium carbonate was added to control the pH of the reaction system to 13. The reaction was stirred at 25°C for 5 hours. After the reaction was completed, the product was washed to obtain a cation exchange resin grafted with crown ether groups.

[0132] The ratio of chloromethylated polystyrene resin, aminobenzo-12-crown-4 and N,N-dimethylamide is 1g:8mL:7mL.

[0133] (4) In a mixed solvent of ethanol and water with a volume ratio of 8:1, ZrOCl2·8H2O was added and stirred to dissolve, resulting in a solution containing ZrOCl2·8H2O. Then, the cation exchange resin grafted with crown ether groups was immersed in the solution containing ZrOCl2·8H2O and stirred at 80°C for 1 h. Subsequently, a phosphoric acid solution with a concentration of 3 mol / L was added, and the reaction was carried out at 90°C for 48 h. After the reaction was completed, the product was washed with deionized water and dried to obtain the lithium extraction adsorbent.

[0134] The solid-liquid ratio of ZrOCl2·8H2O to the mixed solvent is 1g:6mL, the solid-liquid ratio of the cation exchange resin grafted with crown ether groups to the solution containing ZrOCl2·8H2O is 1g:3mL, and the molar ratio of ZrOCl2·8H2O in the solution containing ZrOCl2·8H2O to phosphoric acid in the phosphoric acid solution is 1:1.

[0135] Example 4

[0136] The difference between this embodiment and embodiment 1 is that the solid-liquid ratio of the cation exchange resin grafted with crown ether groups and the solution containing ZrOCl2·8H2O in step (4) is adjusted so that the loading of α-ZrP adsorption active sites is 10wt% of the mass of the resin-based material.

[0137] The remaining preparation methods and parameters are consistent with those in Example 1.

[0138] Example 5

[0139] The difference between this embodiment and embodiment 1 is that the solid-liquid ratio of the cation exchange resin grafted with crown ether groups and the solution containing ZrOCl2·8H2O in step (4) is adjusted so that the loading of α-ZrP adsorption active sites is 80 wt% of the resin-based material mass.

[0140] The remaining preparation methods and parameters are consistent with those in Example 1.

[0141] Example 6

[0142] The difference between this embodiment and embodiment 1 is that in step (4), the molar ratio of ZrOCl2·8H2O in the solution containing ZrOCl2·8H2O to phosphoric acid in the phosphoric acid solution is 1:5.

[0143] The remaining preparation methods and parameters are consistent with those in Example 1.

[0144] Example 7

[0145] The difference between this embodiment and embodiment 1 is that in step (4), the molar ratio of ZrOCl2·8H2O in the solution containing ZrOCl2·8H2O to phosphoric acid in the phosphoric acid solution is 1:0.5.

[0146] The remaining preparation methods and parameters are consistent with those in Example 1.

[0147] Example 8

[0148] The difference between this embodiment and embodiment 1 is that the reaction temperature in step (4) is 70°C.

[0149] The remaining preparation methods and parameters are consistent with those in Example 1.

[0150] Example 9

[0151] The difference between this embodiment and embodiment 1 is that the reaction temperature in step (4) is 150°C.

[0152] The remaining preparation methods and parameters are consistent with those in Example 1.

[0153] Example 10

[0154] The difference between this embodiment and Example 1 is that the molar ratio of benzo-12-crown-4 and nitric acid in step (1) is 1:1.2.

[0155] The remaining preparation methods and parameters are consistent with those in Example 1.

[0156] Example 11

[0157] The difference between this embodiment and Example 1 is that the molar ratio of benzo-12-crown-4 and nitric acid in step (1) is 1:0.5.

[0158] The remaining preparation methods and parameters are consistent with those in Example 1.

[0159] Example 12

[0160] The difference between this embodiment and embodiment 1 is that glacial acetic acid is not added in step (1).

[0161] The remaining preparation methods and parameters are consistent with those in Example 1.

[0162] Example 13

[0163] The difference between this embodiment and embodiment 1 is that hydrazine hydrate is not added in step (2).

[0164] The remaining preparation methods and parameters are consistent with those in Example 1.

[0165] Example 14

[0166] The difference between this embodiment and embodiment 1 is that the ratio of chloromethylated polystyrene resin to aminobenzo-12-crown-4 in step (3) is 1g:15mL.

[0167] The remaining preparation methods and parameters are consistent with those in Example 1.

[0168] Example 15

[0169] The difference between this embodiment and Example 1 is that the ratio of chloromethylated polystyrene resin to aminobenzo-12-crown-4 in step (3) is 1g:5mL.

[0170] The remaining preparation methods and parameters are consistent with those in Example 1.

[0171] Comparative Example 1

[0172] The difference between this comparative example and Example 1 is that step (4) is omitted, and instead, the cation exchange resin grafted with crown ether groups is used directly as the lithium extraction adsorbent.

[0173] The remaining preparation methods and parameters are consistent with those in Example 1.

[0174] Comparative Example 2

[0175] The difference between this comparative example and Example 1 is that the lithium extraction adsorbent provided in this comparative example is an α-ZrP adsorbent, that is, steps (1)-(3) are not performed, and no cation exchange resin grafted with crown ether groups is added in step (4).

[0176] The remaining preparation methods and parameters are consistent with those in Example 1.

[0177] Performance testing

[0178] The lithium-extraction adsorbents prepared in the above examples and comparative examples were placed in brine for adsorption. The brine contained sodium ions, magnesium ions, lithium ions, boron ions, chloride ions, calcium ions, and carbonate ions, with concentrations of 39.0 g / L, 10.3 g / L, 0.7 g / L, 0.75 g / L, 58 g / L, 5.7 g / L, and 2.1 g / L, respectively. The adsorption parameters were: flow rate of 200 BV / h, and adsorption was completed after 3 hours of circulation. After rinsing the adsorbent with water, hydrochloric acid solution with pH 1 was added for desorption at 180 BV / h for 30 minutes of circulation. The Li concentration in the solution before and after adsorption was measured using an atomic absorption spectrophotometer. The adsorption capacity was calculated using the following formula: Qt = (C0 - Ct) × V / m, where Qt is the adsorption capacity of Li+ after adsorption, C0 and Ct are the initial and final Li+ concentrations, respectively, V is the volume of the solution, and m is the weight of the adsorbent.

[0179] The adsorption capacity of the lithium extraction adsorbent after 3 hours and the ion content in the eluent are shown in Table 1.

[0180] Table 1

[0181]

[0182]

[0183] analyze:

[0184] As shown in the table above, the adsorbent provided by this invention has good selective adsorption for Li+ and a high adsorption capacity.

[0185] As can be seen from Examples 1 and 4-5, if the loading of α-ZrP adsorption active sites is too small, the adsorption capacity of the lithium extraction adsorbent will be significantly reduced; if the loading of α-ZrP adsorption active sites is too large, the selectivity of the lithium extraction adsorbent to lithium ions will be reduced, and the impurity ions in the lithium-containing desorption solution will increase.

[0186] As can be seen from Examples 1 and 6-7, if the molar ratio of ZrOCl2·8H2O to phosphoric acid is too small, the reaction rate will decrease and the content of α-ZrP generated will decrease, thereby reducing the capacity of the lithium extraction adsorbent; if the molar ratio of ZrOCl2·8H2O to phosphoric acid is too large, the generated α-ZrP is prone to agglomeration, which will lead to a decrease in the adsorption rate and adsorption capacity of the lithium extraction adsorbent.

[0187] As can be seen from Examples 1 and 8-9, if the reaction temperature in step (4) is too low, the content of generated α-ZrP will decrease, thereby reducing the capacity of the lithium extraction adsorbent; if the reaction temperature in step (4) is too high, the generated α-ZrP will easily agglomerate, which will lead to a decrease in the adsorption rate and adsorption capacity of the lithium extraction adsorbent.

[0188] As can be seen from Examples 1 and 10-11, if the molar ratio of benzo-12-crown-4 to nitric acid is too small, side reactions are likely to occur, which ultimately reduces the number of grafted crown ether groups in the lithium extraction adsorbent, resulting in a decrease in the selectivity of the lithium extraction adsorbent for lithium ions. If the molar ratio of benzo-12-crown-4 to nitric acid is too large, the content of generated aminobenzo-12-crown-4 will be too small, the number of crown ether groups in the lithium extraction adsorbent will decrease, thereby reducing the selectivity of the lithium adsorbent for lithium ions.

[0189] As can be seen from Examples 1 and 12, if glacial acetic acid is not added in step (1), the reaction will be incomplete, the content of nitrobenzene-12-crown-4 formed will be too low, and the number of crown ether groups in the lithium adsorbent will be reduced, thereby causing the lithium adsorbent to decrease its selectivity for lithium ions.

[0190] As can be seen from Examples 1 and 13, if hydrazine hydrate is not added in step (2), aminobenzo-12-crown-4 will not be formed, resulting in too few crown ether groups in the final lithium adsorbent, and the selectivity of the lithium adsorbent for lithium ions will be significantly reduced.

[0191] As can be seen from Examples 1 and 14-15, if the ratio of chloromethylated polystyrene resin to aminobenzo-12-crown-4 is too small, the content of aminobenzo-12-crown-4 on the resin-based material will be too high, the diffusion rate of lithium ions will decrease, and the adsorption capacity of the lithium extraction adsorbent will be reduced. If the ratio of chloromethylated polystyrene resin to aminobenzo-12-crown-4 is too high, the number of crown ether groups with high selectivity for lithium ions on the lithium extraction adsorbent will be too low, thus reducing the selectivity of the lithium extraction adsorbent for lithium ions.

[0192] As can be seen from Example 1 and Comparative Example 1, if the cation exchange resin grafted with crown ether groups is directly used as the lithium extraction adsorbent, the adsorption capacity of the lithium extraction adsorbent is significantly reduced.

[0193] As can be seen from Example 1 and Comparative Example 2, if α-ZrP adsorbent is used as the lithium extraction adsorbent, the selectivity of the lithium extraction adsorbent for lithium ions decreases significantly, and the content of impurity cations in the lithium-containing desorption solution increases significantly.

[0194] The applicant declares that the present invention is illustrated by the above embodiments, but the present invention is not limited to the above process steps, that is, it does not mean that the present invention must rely on the above process steps to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials used in the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. An application of a lithium extraction adsorbent in lithium extraction from salt lakes, characterized in that, The lithium extraction adsorbent comprises a resin-based material grafted with crown ether groups, and α-ZrP adsorption active sites loaded on the surface of the resin-based material. The loading of the α-ZrP adsorption active sites is 30wt%-60wt% of the mass of the resin-based material; The preparation method of the lithium extraction adsorbent includes the following steps: The lithium extraction adsorbent is obtained by mixing a resin-based material grafted with crown ether groups, a solution containing a zirconium source, and a solution containing a phosphorus source, and then reacting the mixture.

2. The application according to claim 1, characterized in that, The resin-based material includes cation exchange resin.

3. The application according to claim 1, characterized in that, The solid-liquid ratio of the resin-based material with grafted crown ether groups and the zirconium-containing solution is 1 g:(3-5) mL.

4. The application according to claim 1, characterized in that, The concentration of the phosphorus source solution is 1.5-3 mol / L.

5. The application according to claim 1, characterized in that, The molar ratio of the zirconium source in the zirconium source solution to the phosphorus source in the phosphorus source solution is 1:(1-3).

6. The application according to claim 1, characterized in that, The mixing methods include: The resin-based material grafted with crown ether groups is blended with a zirconium-containing solution, and then a phosphorus-containing solution is added and mixed.

7. The application according to claim 6, characterized in that, The blending process is accompanied by stirring.

8. The application according to claim 6, characterized in that, The blending temperature is 70-80℃ and the time is 1-2 hours.

9. The application according to claim 1, characterized in that, The reaction is carried out at a temperature of 90-120℃ for 24-48 hours.

10. The application according to claim 1, characterized in that, The preparation steps of the resin-based material grafted with crown ether groups include: (a) Benzo-12-crown-4, organic acid, nitric acid and organic solvent are mixed and reacted to obtain nitrobenzo-12-crown-4; (b) The nitrobenz-12-crown-4, the reducing agent, and the organic solvent are mixed and reacted to obtain aminobenzo-12-crown-4; (c) The resin-based material, the aminobenzo-12-crown-4 and the organic solvent are mixed and reacted to obtain the resin-based material with the grafted crown ether group.

11. The application according to claim 10, characterized in that, In step (a), the solid-liquid ratio of benzo-12-crown-4 and the organic acid is 1 g:(13-17) mL.

12. The application according to claim 10, characterized in that, The molar ratio of benzo-12-crown-4 and nitric acid in step (a) is 1:(0.6-1).

13. The application according to claim 10, characterized in that, The reaction in step (a) is carried out at a temperature of 20-30°C for 12-24 hours.

14. The application according to claim 10, characterized in that, The reducing agent in step (b) includes hydrazine hydrate and / or sodium borohydride.

15. The application according to claim 10, characterized in that, The mass ratio of nitrobenz-12-crown-4 to the reducing agent in step (b) is 1:(0.1-0.3).

16. The application according to claim 10, characterized in that, The reaction in step (b) is carried out at a temperature of 75-85°C for 8-16 hours.

17. The application according to claim 10, characterized in that, In step (c), a pH adjuster is added during the mixing process to make the pH of the resulting mixed solution 9-13.

18. The application according to claim 10, characterized in that, The reaction in step (c) is carried out at a temperature of 25-60°C for 2-5 hours.

19. The application according to claim 10, characterized in that, In step (c), the ratio of the resin-based material, the aminobenzo-12-crown-4, and the organic solvent is 1 g:(8-10) mL:(5-7) mL.

20. The application according to any one of claims 10-19, characterized in that, The preparation method includes the following steps: (1) Dissolve benzo-12-crown-4 in chloroform and add glacial acetic acid, then add nitric acid with a mass concentration of 80-90% dropwise and mix. Then carry out the reaction at 20-30℃ for 12-24h. After the reaction is completed, wash and dry the product to obtain nitrobenzene-12-crown-4. The solid-liquid ratio of benzo-12-crown-4 to chloroform is 1 g:(13-17) mL, the solid-liquid ratio of benzo-12-crown-4 to glacial acetic acid is 1 g:(13-17) mL, and the molar ratio of benzo-12-crown-4 to nitric acid is 1:(0.6-1). (2) The nitrobenz-12-crown-4 was placed in anhydrous ethanol, and then hydrazine hydrate was added. The reaction was carried out at 75-85℃ for 8-16 h. After the reaction was completed, the product was washed and dried to obtain aminobenzo-12-crown-4. The solid-liquid ratio of nitrobenz-12-crown-4 to anhydrous ethanol is 1 g:(15-20) mL, and the mass ratio of nitrobenz-12-crown-4 to hydrazine hydrate is 1:(0.1-0.3). (3) Add the cation exchange resin to N,N dimethylamide and stir evenly, then add the aminobenzo-12-crown-4, and add alkaline substances to control the pH of the reaction system to 9-13. Stir the reaction at 25-60℃ for 2-5 hours. After the reaction is completed, wash the product to obtain the cation exchange resin grafted with crown ether groups. The ratio of cation exchange resin, aminobenzo-12-crown-4 and N,N dimethylamide is 1 g:(8-10) mL:(5-7) mL. (4) In a mixed solvent of ethanol and water with a volume ratio of (6-8):1, add zirconium source and stir to dissolve to obtain a zirconium source-containing solution. Then, immerse the cation exchange resin grafted with crown ether group into the zirconium source-containing solution and stir at 70-80℃ for 1-2h. Then, add phosphoric acid solution with a concentration of 1.5-3mol / L and react at 90-120℃ for 24-48h. After the reaction is completed, wash and dry the product to obtain lithium extraction adsorbent. The solid-liquid ratio of zirconium source and mixed solvent is 1g:(4-6)mL, the solid-liquid ratio of cation exchange resin grafted with crown ether group and zirconium source solution is 1g:(3-5)mL, and the molar ratio of zirconium source in zirconium source solution to phosphoric acid in phosphoric acid solution is 1:(1-3).

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